Generally, an emulsion pump is mounted on a container opening of a bottled product such as body lotion, shampoo and the like. A user may press the emulsion pump to pump out the product in the container. FIGS. 16a and 16b show an emulsion pump presently commonly used. FIG. 16a is a sectional view showing interior structure of the emulsion pump.
As shown in FIG. 16a, the emulsion pump 100 includes a press head 110 with an outlet, a toothed sleeve 120 and a cylinder 130. The toothed sleeve 120 threadedly connects to the opening of a container (not shown), and thus connects the emulsion pump 100 to the container. An end of the cylinder 130 is connected to the toothed sleeve 120, and the other end thereof extends into the container. The emulsion pump 100 is further provided with a piston rod 140, one end of which is fixedly connected to the press head 120, and the other end thereof extends into the cylinder 130. The interior of the piston rod 140 is fluidly communicated with the outlet of the press head 110.
A first spring seat 151 is provided at a lower portion of the piston rod 140, and a second spring seat 152 is provided in the cylinder 130 correspondingly, a compression spring 150 is supported between the first spring seat and the second spring seat 152. The compression spring 150 exerts an upwardly biasing force on the piston rod 140.
As shown in FIG. 16a, the press head 110 and the toothed sleeve 120 are respectively provided with complementary internal and external threads, the press head 110 may be fixed on a locked position with the internal and external threads engaged. The press head 110 may transited from the locked position to an opening position by rotating the press head 110 in an open direction (a counter-clockwise direction) shown by an arrow in FIG. 16b. At the opening position, the piston rod 140 moves upwardly by means of the biasing force of the compression spring 150, and thus the press head 110 moves upwardly.
The cylinder 130 is provided with a first valve 160, and a piston head 170 is provided at the bottom portion of the piston rod 140, the piston head 170 forms a check valve with a corresponding piston. The first valve 160 is also a check valve, and the flow direction thereof is identical to that of the check valve at the piston head 170. When the press head 110 and the piston rod 140 are at the opening position, the user may press the press head 110 downward against the biasing force of the spring 150. At this time, a space between the first valve 160 and the piston rod 140 is reduced, so that the pressure therein raises, by means of which, the product between the first valve 160 and the piston rod 140 flows into the interior of the piston rod 140, and is discharged through the outlet of the press head 110. Upon the press on the press head 110 by the user being releasing, the piston rod 140 moves upwardly together with the press head 110 by means of the upwardly biasing force of the press head 110, at this time, the space between the first valve 160 and the piston rod 140 expands, during which the piston moves downward relative to the piston head 170 with the friction force applied by the cylinder to the piston, and thus closes the corresponding check valve. At this time, the pressure between the first valve 160 and the piston rod 140 decreases, and by means of such differential pressure, the first valve 160 opens, and thus allows the liquid in the container to flow into the space between the first valve 160 and the piston rod 140.
Nowadays, with the fast development of the E-commerce, the existing emulsion pump presents some problems. Specifically, during transportation of the bottled product by express delivery, a tubular press mouth of the emulsion pump may undergo torque due to some reasons such as impact, drop and the like, thus resulting rotation of the press head. If the press head rotates in the opening direction, i.e. the counter-clockwise direction, it is possible that the press head may be turned to its opening position, and thus springs up. At this time, if the press head is pressed downward, the liquid in the container may be pumped out. Also, the direction of the thread connection between the toothed sleeve and the container is identical to that of the thread connection between the press head and the toothed sleeve, that is, when the press head rotates in the opening direction, i.e. the counter-clockwise direction, by means of the torque exerted on the press mouth, it is possible that the toothed sleeve loosens from the opening of the container, resulting in leakage of liquid from the container. Furthermore, no matter the press mouth is exerted by a torque in the counter-clockwise direction or clockwise direction, there is a risk of the press mouth being broken by impact.
So, there is a need for a novel emulsion pump used for a bottled product, which can overcome the aforementioned problems.